From ae162109397dc68bbc68fa0c22331427628f6942 Mon Sep 17 00:00:00 2001 From: Larry Bugbee Date: Thu, 17 Aug 2017 21:06:50 -0700 Subject: [PATCH 1/4] Delete demo_dynamic.py --- demos/demo_dynamic.py | 281 ------------------------------------------ 1 file changed, 281 deletions(-) delete mode 100644 demos/demo_dynamic.py diff --git a/demos/demo_dynamic.py b/demos/demo_dynamic.py deleted file mode 100644 index 51aaf33..0000000 --- a/demos/demo_dynamic.py +++ /dev/null @@ -1,281 +0,0 @@ - - -""" - demo_dynamic.py v2b - - This program demonstrates Python's use of the dynamic - language support additions to LTC, namely access to LTC - constants, struct and union sizes, and the binding of a - math package to LTC. Also provided are simple code - fragments to illustrate how one might write a Python - wrapper for LTC and how an app might call the wrapper. - This or a similar model should work for Ruby and other - dynamic languages. - - This instance uses Python's ctypes and requires a single - .dylib linking together LTC and a math library. Building - a single .dylib is needed because LTC wants a fairly tight - relationship between itself and the mathlib. (ctypes can - load multiple .dylibs, but it does not support this level - of tight coupling between otherwise independent libraries.) - - My .dylib was created on OSX/macOS with the following: - sudo make -j5 -f makefile.shared \ - CFLAGS="-DUSE_TFM -DTFM_DESC -I/usr/local/include" \ - EXTRALIBS=/usr/local/lib/libtfm.a install - - For python 2.7.12 on Ubuntu Xenial the following worked for - me (without MPI support): - sudo make -f makefile.shared install PREFIX="/usr" - - Reminder: you don't need to bind in a math library unless - you are going to use LTC functions that need a - mathlib. For example, public key crypto requires - a mathlib; hashing and symmetric encryption do not. - - This code was written for Python 2.7 with the ctypes standard - library. - - Larry Bugbee - March 2014 v1 - August 2017 v2b - -""" - - -from ctypes import * -from ctypes.util import find_library - -# switches to enable/disable selected output -SHOW_ALL_CONSTANTS = True -SHOW_ALL_SIZES = True -SHOW_SELECTED_CONSTANTS = True -SHOW_SELECTED_SIZES = True -SHOW_BUILD_OPTIONS_ALGS = True -SHOW_SHA256_EXAMPLE = True -SHOW_CHACHA_EXAMPLE = True - -print -print(' demo_dynamic.py') - - -#------------------------------------------------------------------------------- -# load the .dylib - -libname = 'tomcrypt' -libpath = find_library(libname) -print -print(' path to library %s: %s' % (libname, libpath)) - -LTC = cdll.LoadLibrary(libpath) -print(' loaded: %s' % LTC) -print - - -#------------------------------------------------------------------------------- -# get list of all supported constants followed by a list of all -# supported sizes. One alternative: these lists may be parsed -# and used as needed. - -if SHOW_ALL_CONSTANTS: - print '-'*60 - print ' all supported constants and their values:' - - # get size to allocate for constants output list - str_len = c_int(0) - ret = LTC.crypt_list_all_constants(None, byref(str_len)) - print ' need to allocate %d bytes to build list \n' % str_len.value - - # allocate that size and get (name, size) pairs, each pair - # separated by a newline char. - names_sizes = c_buffer(str_len.value) - ret = LTC.crypt_list_all_constants(names_sizes, byref(str_len)) - print names_sizes.value - print - - -if SHOW_ALL_SIZES: - print '-'*60 - print ' all supported sizes:' - - # get size to allocate for sizes output list - str_len = c_int(0) - ret = LTC.crypt_list_all_sizes(None, byref(str_len)) - print ' need to allocate %d bytes to build list \n' % str_len.value - - # allocate that size and get (name, size) pairs, each pair - # separated by a newline char. - names_sizes = c_buffer(str_len.value) - ret = LTC.crypt_list_all_sizes(names_sizes, byref(str_len)) - print names_sizes.value - print - - -#------------------------------------------------------------------------------- -# get individually named constants and sizes - -if SHOW_SELECTED_CONSTANTS: - print '-'*60 - print '\n selected constants:' - - names = [ - 'ENDIAN_LITTLE', - 'ENDIAN_64BITWORD', - 'PK_PUBLIC', - 'MAX_RSA_SIZE', - 'CTR_COUNTER_BIG_ENDIAN', - ] - for name in names: - const_value = c_int(0) - rc = LTC.crypt_get_constant(name, byref(const_value)) - value = const_value.value - print ' %-25s %d' % (name, value) - print - -if SHOW_SELECTED_SIZES: - print '-'*60 - print '\n selected sizes:' - - names = [ - 'rijndael_key', - 'rsa_key', - 'symmetric_CTR', - 'twofish_key', - 'ecc_point', - 'gcm_state', - 'sha512_state', - ] - for name in names: - size_value = c_int(0) - rc = LTC.crypt_get_size(name, byref(size_value)) - value = size_value.value - print ' %-25s %d' % (name, value) - print - - -#------------------------------------------------------------------------------- -#------------------------------------------------------------------------------- -# LibTomCrypt exposes one interesting string that can be accessed -# via Python's ctypes module, "crypt_build_settings", which -# provides a list of this build's compiler switches and supported -# algorithms. If someday LTC exposes other interesting strings, -# they can be found with: -# nm /usr/local/lib/libtomcrypt.dylib | grep " D " - -def get_named_string(lib, name): - return c_char_p.in_dll(lib, name).value - -if SHOW_BUILD_OPTIONS_ALGS: - print '-'*60 - print 'This is a string compiled into LTC showing compile ' - print 'options and algorithms supported by this build \n' - print get_named_string(LTC, 'crypt_build_settings') - - -#------------------------------------------------------------------------------- -#------------------------------------------------------------------------------- -# here is an example of how Python code can be written to access -# LTC's implementation of SHA256 and ChaCha, - -# - - - - - - - - - - - - - -# definitions - -def _get_size(name): - size = c_int(0) - rc = LTC.crypt_get_size(name, byref(size)) - if rc != 0: - raise Exception('LTC.crypt_get_size(%s) rc = %d' % (name, rc)) - return size.value - -def _get_constant(name): - constant = c_int(0) - rc = LTC.crypt_get_constant(name, byref(constant)) - if rc != 0: - raise Exception('LTC.crypt_get_constant(%s) rc = %d' % (name, rc)) - return constant.value - -def _err2str(err): - # define return type - errstr = LTC.error_to_string - errstr.restype = c_char_p - # get and return err string - return errstr(err) - -CRYPT_OK = _get_constant('CRYPT_OK') - -class SHA256(object): - def __init__(self): - self.state = c_buffer(_get_size('sha256_state')) - LTC.sha256_init(byref(self.state)) - def update(self, data): - LTC.sha256_process(byref(self.state), data, len(data)) - def digest(self): - md = c_buffer(32) - LTC.sha256_done(byref(self.state), byref(md)) - return md.raw - -class ChaCha(object): - def __init__(self, key, rounds): - self.state = c_buffer(_get_size('chacha_state')) - self.counter = c_int(1) - err = LTC.chacha_setup(byref(self.state), key, len(key), rounds) - if err != CRYPT_OK: - raise Exception('LTC.chacha_setup(), err = %d, "%s"' % (err, _err2str(err))) - def set_iv32(self, iv): - err = LTC.chacha_ivctr32(byref(self.state), iv, len(iv), byref(self.counter)) - if err != CRYPT_OK: - raise Exception('LTC.chacha_ivctr32(), err = %d, "%s"' % (err, _err2str(err))) - def crypt(self, datain): - dataout = c_buffer(len(datain)) - err = LTC.chacha_crypt(byref(self.state), datain, len(datain), byref(dataout)) - if err != CRYPT_OK: - raise Exception('LTC.chacha_crypt(), err = %d, "%s"' % (err, _err2str(err))) - return dataout.raw - -# - - - - - - - - - - - - - -# a SHA256 app fragment - -# from wrapper import * # uncomment in real life - -if SHOW_SHA256_EXAMPLE: - print '-'*60 - data = 'hello world' - - sha256 = SHA256() - sha256.update(data) - md = sha256.digest() - - template = '\n the SHA256 digest for "%s" is %s \n' - print template % (data, md.encode('hex')) - -# - - - - - - - - - - - - - -# a ChaCha app fragment - -if SHOW_CHACHA_EXAMPLE: - print '-'*60 - key = 'hownowbrowncow\x00\x00' # exactly 16 or 32 bytes - rounds = 12 # common values: 8, 12, 20 - iv = '123456789012' # exactly 12 bytes - plain = 'Kilroy was here, there, and everywhere!' - - cha = ChaCha(key, rounds) - cha.set_iv32(iv) - cipher = cha.crypt(plain) - - template = '\n ChaCha%d ciphertext for "%s" is "%s"' - print template % (rounds, plain, cipher.encode('hex')) - - # reset to decrypt - cha.set_iv32(iv) - decrypted = cha.crypt(cipher) - - template = ' ChaCha%d decoded text for "%s" is "%s" \n' - print template % (rounds, plain, decrypted) - -# Footnote: Keys should be erased fm memory as soon as possible after use, -# and that includes Python. For a tip on how to do that in Python, see -# http://buggywhip.blogspot.com/2010/12/erase-keys-and-credit-card-numbers-in.html - -#------------------------------------------------------------------------------- -#------------------------------------------------------------------------------- -#------------------------------------------------------------------------------- From 631de35ee37e7e51b2bf5cd729798f9e6b58107c Mon Sep 17 00:00:00 2001 From: Larry Bugbee Date: Thu, 17 Aug 2017 21:11:59 -0700 Subject: [PATCH 2/4] Update and rename demo_dynamic.py3 to demo_dynamic.py this version runs under python2 and python3 so only one version need be distributed --- demos/{demo_dynamic.py3 => demo_dynamic.py} | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) rename demos/{demo_dynamic.py3 => demo_dynamic.py} (99%) diff --git a/demos/demo_dynamic.py3 b/demos/demo_dynamic.py similarity index 99% rename from demos/demo_dynamic.py3 rename to demos/demo_dynamic.py index f73d617..c29df49 100644 --- a/demos/demo_dynamic.py3 +++ b/demos/demo_dynamic.py @@ -1,7 +1,7 @@ """ - demo_dynamic.py3 v2b + demo_dynamic.py v2b This program demonstrates Python's use of the dynamic language support additions to LTC, namely access to LTC From 3794ecaf942de766aaef944345e2f95fbe8ab779 Mon Sep 17 00:00:00 2001 From: Larry Bugbee Date: Fri, 18 Aug 2017 20:34:03 -0700 Subject: [PATCH 3/4] Update demo_dynamic.py removed trailing spaces --- demos/demo_dynamic.py | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) diff --git a/demos/demo_dynamic.py b/demos/demo_dynamic.py index c29df49..6c21f92 100644 --- a/demos/demo_dynamic.py +++ b/demos/demo_dynamic.py @@ -34,17 +34,17 @@ a mathlib; hashing and symmetric encryption do not. ------ - + This code was originally written for Python 2.7 with the ctypes standard library. This version was modified so that it would run under both Python 2.7 and 3.6. You might want to run a diff on the .py and .py3 files to see the differences - between the two languages. - + between the two languages. + Arguably the biggest change for Python3 has to do with strings. Under Python2, native strings are ASCII bytes and passing them to LTC is natural and requires no conversion. - Under Python3 all native strings are Unicode which requires + Under Python3 all native strings are Unicode which requires they be converted to bytes before use by LTC. Note the following for Python3. @@ -56,11 +56,10 @@ If so, use .decode('utf-8'). - The Python2 'print' statement becomes a function in Python3 which requires parenthesis, eg. 'print()'. - + NB: Unicode is achieved under Python2 by either defining a Unicode string with a 'u' prefix or passing ASCII strings thru the 'unicode()' function. - Larry Bugbee March 2014 v1 From de6ac748c77732ccae289a696fdc88852916be48 Mon Sep 17 00:00:00 2001 From: Larry Bugbee Date: Sat, 19 Aug 2017 16:29:48 -0700 Subject: [PATCH 4/4] refine comments --- demos/demo_dynamic.py | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/demos/demo_dynamic.py b/demos/demo_dynamic.py index 6c21f92..dbfb10a 100644 --- a/demos/demo_dynamic.py +++ b/demos/demo_dynamic.py @@ -36,10 +36,8 @@ ------ This code was originally written for Python 2.7 with the - ctypes standard library. This version was modified so that - it would run under both Python 2.7 and 3.6. You might want - to run a diff on the .py and .py3 files to see the differences - between the two languages. + ctypes standard library. This version is modified to run + under both Python 2.7 and 3.6. Arguably the biggest change for Python3 has to do with strings. Under Python2, native strings are ASCII bytes and